Abstract According to the 2014 U.S. National Health Interview Survey, 5.5% of adults aged 18-39 years old self- reported trouble with hearing without a hearing aid. Among adults 40-69 years of age, the rate was 19% increasing to 43% among adults aged 70 and over with 63% reporting mild hearing loss. To date, there has been no published results from these survey data of people living with HIV (PLWH) due to lack of reported HIV status. In a pilot study of middle-aged and aging HIV positive and HIV seronegative men and women conducted in Washington DC and Baltimore, HIV infection was associated with low and high frequency hearing loss. But, more rigorous studies are needed, especially as more than half of PLWH in the U.S. are over the age of 50 years old. Besides age and race/ethnicity differences in hearing and balance, being overweight, increased alcohol consumption, smoking, less physical activity, the occurrence of hypertension and diabetes are common risk factors for hearing and balance problems. These risk factors may also be higher in PLWH and share a common hallmark of inflammation and immune activation. Furthermore, hearing and balance problems may contribute to neurocognitive and physical dysfunction, which are also of concern in aging PLWH. Finally, there is no research on the use of hearing testing applications in adults with HIV. Evaluation of the feasibility of using a hearing testing application and the accuracy of a smartphone hearing testing application in PLWH and their HIV seronegative counterparts are needed. We propose to address these gaps in knowledge by implementing cohort-wide administration of the NHANES hearing (and balance questionnaire) in the MACS-WIHS Combined Cohort Study (MWCCS) in approximately 4,100 active middle aged and aging men and women living with and without HIV. In a subset of participants from the Washington-DC and Baltimore sites with baseline hearing and balance data collected in 2009-2010 with follow-up testing in 2020-2021, we propose to investigate whether the trajectory of markers of immune activation and inflammation contribute to progression of hearing and balance issues, and whether a smartphone hearing test application may be a feasible method to capture hearing trouble in PLWH compared to HIV seronegative participants.